P89 · Packing and covering · Classic

Tans in a square

VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION
n = 6Current record · open

Pack n tans (right isosceles triangles of leg 1) into a square. Contact is allowed; interiors cannot overlap. Minimise the container square side.

Formal definition

  • ContainerThe editor and certificate normalize to the unit square [0,1]². This is a coordinate convention only; scores use the literature's unit-piece scale. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn,quarter},…]}, with x, y and turn as decimal strings of at most nine places. radius is the piece's short side (the leg, the domino's short side, the cell side); the container side is 1/radius. x,y is the centre of the piece's bounding box; quarter is an integer 0–3, an exact number of right angles applied about the centre before the rational turn = tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.
  • ConstraintsExactly n congruent shapes lie wholly in the container with pairwise disjoint interiors. Polygon rotations are independent, not limited to quarter turns.
  • PrecisionInput decimals are exact rationals; regular-polygon vertices are algebraic, not rounded templates. Feasibility has no floating-point tolerance. A finite-decimal certificate is not a continuous optimality proof.
  • Objectivecontainer square side = 1/r (r is the piece's short side inside the unit square), smaller is better. Pages, leaderboards and literature records share this unit; nothing is converted by hand.

Getting a feel for it

Source and certificate

External targets are converted with their printed precision; decimal coordinate certificates are separate. Reconstruction loss never lowers the literature target, and a source construction is not automatically an optimality proof.

Source
ONE LEADERBOARD PER n

Current best solutions by n

Each n is an independent record with a page of its own. Open any of them to inspect the current construction, then challenge it.

Discussion (0) ↓
n1
CURRENT RECORD1Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n2
CURRENT RECORD1Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n3
CURRENT RECORD1.414213621Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n4
CURRENT RECORD1.414213621Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n5
CURRENT RECORD1.788569824best known 1.788
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n6
CURRENT RECORD1.937914833best known 1.937
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n7
CURRENT RECORD1.999598089best known 1.999
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n8
CURRENT RECORD2Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n9
CURRENT RECORD2.207106837best known 2.207
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n10
CURRENT RECORD2.393754586best known 2.393
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n11
CURRENT RECORD2.414213612best known 2.414
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n12
CURRENT RECORD2.611150004best known 2.61115
Matches the best known
Answer sourceHaowei Lin
Solution methodPublished reference construction
n13
CURRENT RECORD2.688240167best known 2.688
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n14
CURRENT RECORD2.763450004best known 2.76345
Matches the best known
Answer sourceHaowei Lin
Solution methodPublished reference construction
n15
CURRENT RECORD3.000000004best known 2.82735
Hard
Record holderFounding benchmark
Solution methodHuman
n16
CURRENT RECORD2.828427242Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n17
CURRENT RECORD2.970710991best known 2.970
Matches the best known
Answer sourceDavid W. Cantrell
Solution methodPublished reference construction
n18
CURRENT RECORD3.000000004Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n19
CURRENT RECORD3.201496211best known 3.201
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n20
CURRENT RECORD3.268570008best known 3.26857
Matches the best known
Answer sourceAapo Lippoen
Solution methodPublished reference construction
n21
CURRENT RECORD3.340065737best known 3.340
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n22
CURRENT RECORD3.392767024best known 3.392
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n23
CURRENT RECORD3.46400001best known 3.464
Matches the best known
Answer sourceMaurizio Morandi
Solution methodPublished reference construction
n24
CURRENT RECORD3.517000007best known 3.517
Matches the best known
Answer sourceDavid W. Cantrell
Solution methodPublished reference construction

Data and citation

Every sub-problem in this family — authoritative scores, proof status, coordinates and sources — lives at the stable address below, published under CC BY 4.0. Scores move as records fall, so cite the generatedAt timestamp the file carries.

GET https://minmaxarena.com/data/tans-in-square.json

Cite the frozen 2026-08 edition: records move, a frozen edition never does, so the citation is still checkable years later.

GET https://minmaxarena.com/data/editions/2026-08/tans-in-square.json
BibTeX (click to copy)
@misc{minmaxarena-tans-in-square-2026-08,
  title  = {{Tans in a square} (P89)},
  author = {{MinMax Arena}},
  year   = {2026},
  note   = {Machine-verified records, 2026-08 edition},
  url    = {https://minmaxarena.com/data/editions/2026-08/tans-in-square.json},
  license = {CC BY 4.0}
}
DISCUSSION

Discussion

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